Automatically optimizes your pages to minimize the number of network connections and ensure even third party resources won't slow down page rendering.
https://www.cloudflare.com/features-optimizer
Analytics and Tracking · Application Performance
Get access to data on 555,755 websites that are Cloudflare Rocket Loader Customers. We know of 31,283 live websites using Cloudflare Rocket Loader and an additional 524,472 sites that used Cloudflare Rocket Loader historically and 15,902 websites in the United States.
Get a list of 555,755 websites using Cloudflare Rocket Loader which includes location information, hosting data, contact details, 53,806 currently live websites which includes 22,523 domains that redirect to sites in the list. 524,472 sites that used this technology previously and 15,902 websites in the United States currently using Cloudflare Rocket Loader.